Pulsed lasers in photovoltaic technology

Schottky diodes have been made on both n-type and p-type virgin mono-crystalline silicon processed by three kinds of pulsed lasers currently used in new photovoltaic technologies. The electrical characteristics of these diodes have been measured as a function of laser fluence. A strong change in all of their electrical parameters occurs for fluence equal or higher than a threshold at which the processed silicon surface layer turns into melt. Capacitance versus voltage measurements and DLTS analyses show that laser irradiations introduce a large density of deep levels related to active defects in the processed surface and bulk area. These defects are believed mostly generated during the fast quenching rate in pulsed laser treatments.